1. Field of the Invention
The present invention relates to a high-voltage discharge lamp lighting apparatus which is formed by integrating a high-voltage pulse generating transformer of a lighting apparatus to a lamp base such as a high-voltage discharge lamp and a floodlight projector, and a high-voltage discharge lamp apparatus and a floodlight projector apparatus using the lighting apparatus.
2. Description of the Related Art
Conventionally, a headlight lamp for automobile, e.g., a metal halide lamp high-voltage discharge lamp uses a high-voltage discharge lamp apparatus which is controlled such that high power is turned on upon starting and fast starting operation is obtained by using a stabilizer and a high-voltage generating apparatus (hereinafter, referred to as an ignitor circuit) for generating a high-voltage start pulse upon starting the light-on operation.
Hereinbelow, a description is given of the high-voltage discharge lamp lighting apparatus used for the headlight for automobile.
Referring to FIG. 10, the conventional high-voltage discharge lamp lighting apparatus comprises: a stabilizer 72 which supplies a power voltage necessary for maintaining the lighting operation to a high-voltage discharge lamp 80 based on a DC voltage from a DC power supply (not shown); and an ignitor circuit comprising an oscillating circuit-for-driving 73, which generates a start pulse upon starting the lighting operation of the high-voltage discharge lamp 80, and a high-voltage pulse generating transformer (hereinafter, abbreviated to a high-voltage pulse transformer) 74, which increases the voltage of the start pulse and generates a high-voltage pulse.
Referring to FIG. 10, the high-voltage discharge lamp lighting apparatus with the above-mentioned structure comprises a cap portion 76 which supports and fixes the high-voltage discharge lamp 80, and a socket portion 71 which is fit into the cap portion 76, and the cap portion 76 can be fit into the socket portion 71 and be detached therefrom. The cap portion 76 comprises connecting pieces 77a and 77b which are connected to electrode leads at both terminals of the high-voltage discharge lamp 80. The socket portion 71 into which the cap portion 76 is fit and attached comprises a connecting piece 75a which connects one output terminal of the stabilizer 72, and a connecting piece 75b which connects one end portion of a secondary coil 74b of the high-voltage pulse transformer 74.
A power voltage for starting the lighting operation and a power voltage necessary for maintaining the lighting operation are supplied to the high-voltage discharge lamp 80 by connecting the connecting pieces 77a and 77b in the cap portion 76 of the high-voltage discharge lamp 80 to the connecting pieces 75a and 75b in the socket portion 71.
That is, a lighting operation switch (not shown) in the high-voltage discharge lamp lighting apparatus is turned on and, then, the stabilizer 72 is driven. Next, the stabilizer 72 superimposes the high-voltage pulse generated by the high-voltage pulse transformer 74 to an AC power voltage necessary for maintaining the lighting operation supplied from a DC/AC inverter (not shown) in the stabilizer 72, based on the oscillating operation caused by charging and discharging of the oscillating circuit-for-driving 73, and supplies the superimposed voltage to the high-voltage discharge lamp 80.
As mentioned above, the lighting operation of the high-voltage discharge lamp 80 is started by the high-voltage pulses generated by the high-voltage pulse transformer 74, and the lighting operation is maintained by the AC power voltage necessary for maintaining the lighting operation from the stabilizer 72 after starting the lighting operation.
When the cap portion 76 in the high-voltage discharge lamp 80 is fit into and is attached to the socket portion 71 and the stabilizer 72 and the oscillating circuit 73 for driving are driven, an operator detaches the cap portion 76 from the socket portion 71 so as to replace the high-voltage discharge lamp 80 and, then, the stabilizer 72 drives the oscillating circuit 73 for driving, similarly to the start of the lighting operation of the high-voltage discharge lamp 80. Further, the stabilizer 72 generates the high-voltage pulses at the secondary coil 74b in the high-voltage pulse transformer 74, thereby generating the high-voltage pulses between the connecting pieces 75a and 75b of the socket portion 71. When the operator touches the connecting pieces 75a and 75b in this state, there is a danger for getting an electric shock.
In addition to the conventional art shown in FIG. 10, another examples of conventional art are: (1) the cap portion 76 includes the oscillating circuit 73 for driving and the high-voltage pulse transformer 74 and the socket portion 71 comprises only the stabilizer 72, (2) the cap protein 76 contains the high-voltage pulse transformer 74 and the socket portion 71 comprises the oscillating circuit 73 for driving and the stabilizer 72, and the like.
However, the conventional arts (1) and (2) have problems that the cap portion and the socket portion need four connecting pieces, respectively, the shape of the cap portion becomes large, and the high-voltage pulse transformer must be replaced together because the cap portion includes at least the high-voltage pulse transformer upon replacing the high-voltage discharge lamp and the replacement costs of high-voltage discharge lamp are increased.